net: do not acquire dev->tx_global_lock in netdev_watchdog_up()

Marek Szyprowski reported a deadlock during system resume when virtio_net
driver is used.

The deadlock occurs because netif_device_attach() is called while holding
dev->tx_global_lock (via netif_tx_lock_bh() in virtnet_restore_up()).
netif_device_attach() calls __netdev_watchdog_up(), which now also tries
to acquire dev->tx_global_lock to synchronize with dev_watchdog().

This recursive lock acquisition results in a deadlock.

Fix this by removing the tx_global_lock acquisition from netdev_watchdog_up().

The critical state (watchdog_timer and watchdog_ref_held) is already
protected by dev->watchdog_lock, which was introduced in the blamed commit.

Fixes: 8eed5519e496 ("net: watchdog: fix refcount tracking races")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/netdev/a443376e-5187-4268-93b3-58047ef113a8@samsung.com/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260622110108.69541-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions